The present invention relates to electrical equipment and, more specifically, to the protection of the electrical equipment against damage due to abnormal overpower conditions being in effect.
A computer system backplane is typically a multi-layer substrate that includes a plurality of conductive layers interleaved with a plurality of dielectric layers. The backplane carries parallel multi-terminal sockets that receive, in an edgewise manner, circuit boards on which computer system components are constructed. Some of the backplane conductive layers are used for signal propagation while other conductive layers are used to distribute power necessary for system operations. These conductive layers are known as “power-planes” and are generally provided in the form of solid sheets of conductive material.
Each multi-terminal socket typically includes a plurality of pins that pass through small, plated vias that are bored through the layers of the backplane. Each pin makes contact with a desired one of the backplane conductive layers. Where no connection to a particular conductive layer is desired, a region surrounding that via and through that conductive layer is insulated to prevent the pin from making contact. The plated vias are sized relative to the connector pins for a press fit. Power supply connections are made in a generally similar manner.
In each power-plane, some of the plated vias make contact with load pins. These are pins that are coupled to the circuit boards received by the sockets. Other vias are connected to source pins. These are pins that are coupled to one or more power supplies.